But the key words in what Gord posted are "...at the end of A sheet." And
THE Key Word in that phrase being "A": singular.
Yes, deleting and inserting rows does affect grouped sheets, just as typing
an entry or formula into a cell causes it to appear on all grouped sheets.

Wise to have notes to remind yourself of such behavior.

"Evan Weiner" wrote:

A year ago Gord Dibben posted a way to delete blank rows at the end of a
sheet. If sheets are grouped (all selected), they seem to get the same
truncation. This can be a rude awakening, especially if the book is not
backed up. My notes now say:

Ungroup sheets
Select row after last useful one
Ctl-Shift-End
Edit Delete... Entire row
Save document